Single sash gang sawmill



March 3, 1959 A. WOODRUFF SINGLE sAsH GANG sAwMILL 4 Sheets-Sheet 1 Filed Aug. 51. 1954 .9 mm. @N

'mnentor: y ALVIN WQODRUFF,

March 3, 1 959 A WOQDRUFF 2,875,795

A SINGLE sAsH GANG SAWMILL Filed Aug. 31, 1954 4 sheets-sheet 2 www vvv- 4"Im, nventnr:

ALVIN WOODRUFF BMW March 3, i959 A WOODRUFF SINGLE sAsH GANG SAWMILL Filed Aug. 3l. 1954 4 Sheets-Sheet 5 ALVIN WOODRUFF,

Gttomeyg's March 3, 1959 A. woo-DRUFF SINGLE sAsH GANG SAWMILL 4 Sheets-Sheet 4 Filed Aug. 51, 1954 mumrtor: ALVIN WOODRUFF,

f ma( l (Ittomegs United States Patent() SINGLE SASH GANG SAWMILL Alvin Woodru, Dallas, Oreg.

Application August 31, 1954, Serial No. 453,290

3 Claims. (Cl. 143-60) This invention relates to sawmills of reciprocative gang saw type, and is concerned particularly with providing an improved single sash gang sawmill for heavy lumbering operations.

Conventional sawmills of this type require anchoring to a massive concrete foundation, and, even then, often vibrate so violently as to make for very considerable operative difficulties.

. One object of the present invention is to largely eliminate vibration, so that the machine may be operated with little or no anchorage, and so that there is a substantial increase in cutting smoothness and eiiciency.

Another object is to eliminate the principal source of friction accompanying operation of conventional sawmills,

specifically the rubbing friction encountered in reciprocation of the saw sash within conventional slideway guides.

As presently constructed, sawmills of the type con cerned are exceedingly costly to build and are expensive to maintain in efficient operating condition. Accordingly, it is also an object of the invention to greatly reduce initial construction and installation costs, and to largely eliminate expensive maintenance and repairs.

Vibration is almost entirely eliminated and smoothness and efficiency of cut greatly enhanced in my new sawmill by reason of an improved system of counterbalances for the reciprocating saw sash. Additional cutting smoothness and efficiency are attained and construction costs considerably reduced by a combinationof such counterbalancing system with a unique mounting for the saw sash, which mounting is of pivotal character and constrains movement of the sash to a truly rectilinear reciprocative path, without the necessity of slideway guides and unaccompanied by side thrust, despite transmission of motion by an arrangement based on the conventional crank and connecting rod. i

A feature of the pivotal mounting for the saw sash is the provision of an assembly of rigid suspension arms pivotally securing the saw sash to respective floating pivots, which are, in turn, rigidly connected to respective suspension pivots xed to the structural framework of the sawmill. Linkage, which articulates transversely of the plane of the saw sash, interconnects floating pivots at one side of the saw sash through lever arms rigid with a corresponding suspension arm and with one of the floating pivots, respectively, While synchronizing linkage, which is non-articulative, interconnects floating pivots at the opposite side of the saw sash through lever arms rigid with the respective floating pivots.

Further objects and features of the invention will become apparent from the following detailed description of the preferredspecic construction illustrated by way of example in the accompanying drawings.

In the drawings:

Fig. 1 represents a front elevation of a typical sawmill embodying the invention and shown with the saw sash at the upper limit of its reciprocative stroke, various con` ice 2 ventional parts being broken out or eliminated entirely for convenience of illustration and clarity of explanation;

Fig. 2, a side elevation viewed from the right in Fig. l, the drive mechanism for the feed rolls and portions of the supporting frame being broken out to reveal the saw sash and its pivotal mounting from the viewpoint of the line 2 2 of Fig. l;

Fig. 3, a top plan taken from the standpoint `of Fig. 2;

Fig. 4, a horizontal 'section taken on the line 4 4 of Fig. 2, showing the saw sash and its pivotal mounting in top plan and over a considerably enlarged scale;

Fig. 5, a vertical section taken on the line 5 5 of Fig. 3;

Fig. 6, a diagrammatic representation corresponding to Fig. 1, but showing the positions of the counterweghts at approximately the mid position of the reciprocative downstroke of the saw sash;

Fig. 7, a similar view, but taken at the lower limit of the reciprocative stroke of the saw sash;

Fig. 8, a similar view, but taken at approximately the mid position of the reciprocative upstroke: of the saw sash;

Fig. 9, a motion diagram showing, in side elevation, the saw sash and the articulative linkage portion of its pivotal mounting in various positions assumed during operation;

Fig. lO, a corresponding motion diagram in opposite side elevation, showing the saw sash and the non-articula tive, synchronizing linkage portion of its pivotal n1ount-l ing; and

Y Fig. 1l, a geometric representation of the saw sash and pivotal mounting of Figs. 9 and l0.

Referring now to the drawings:

The illustrated sawmill, which embodies a presently preferred form of the invention, utilizes conventional mechanism for feeding the logs or cants into and for advancing them through a reciprocating saw sash 10 equipped with a plurality of rectilinear saw blades 11v disposed in side by side, gang formation. Such mechanism includes lower feed rolls 12 and 13 of conventional tinted formation disposed at front and rear of the saw sash, and upper feed rolls (not shown) of similar formation and similarly disposed. The front and rear set of rolls are mounted in respective, preferably hydraulicallyactuated gates of conventional type, as indicated fragmentarily at 14.

The operating mechanism of the sawmill is carried by a structural framework, made up in this instance of a structural base 15 and of upright end frames 16, which are spaced apart laterally of and rigidly secured to the base.

The end Iframes are rigidly connected across their upper ends by a top structure 17. I

The saw sash 10 is mounted in upright position between the respective sets of feed rolls lfor vertical rectilinear reciprocation across the path of travel through the mill of the logs or cants. It is generally desirable to provide oscillating mechanism of conventional type (not shown) in operative connection with the saw sash, for slightly moving the bottom of such sash backwardly immediately prior to commencing each upstroke, so advance ofthe log or cant through the mill will be smooth.

The saw sash mounting is of unique pivotal construction, and will be described in detail hereinafter.

Saw sash 10 is reciprocated by means of a crank and?v connecting rod type of drive connection with any suit-y able source of power. Ordinarily, the source of power.`

Patented Mar. 3, 1959 second crankshaft having a similar drive connection with the opposite side of the saw sash. The pair of mutually opposed counterweights are associated with the respective crankshafts in fixed relationship with the shaft portions thereof, forl rotation therewith in counterbalancing relation to the reciprocative load. Preferably, such counterweights are formed integrally with the crankshafts in' a manner contributing to the formation of the cranks thereof.

In the illustrated preferred construction, the drive pulley 18 is fixed on one end of a crankshaft 1%, which is journaled in spaced bearings 2t) upon the upper frame structure 17 of the supporting framework of the machine. A crank l9a is formed at the opposite end of the crankshaft 1,9, and is connected in reciprocating drive relationship with one side of the saw sash Iii by means of a connecting rod 21.

A second crankshaft 22, see especially Fig. 3, is similarlyjournaled for rotation upon the upper frame structure 17", and is connected to the opposite side of saw sash 10, in similar reciprocative drive relationship, by meansof a connecting rod 23 attached to crank 22a.

The crankshaft 19 is intergeared with the crankshaft 22 by'intermeshing spur gears 19-1 and 22-1,V Fig. l, of equal size, fixed to the respective crankshafts and enclosed by an oil-retaining housing 24. Thus, the two crankshafts are smoothly driven in4 opposite directions atlthe same speed.

Mutually similar counterweights 25 are respectively and correspondingly incorporated in the respective crankshafts,r as by welding in the manner shown, to facilitate formation of the cranks 19a and 22a. Thus, theyare aflixed to such crankshafts, for rotation therewith in mutually opposed relationship and in counterbalancing relationship with respect to the saw sash 10.

For best results, each counterweight 25 has a weight which is somewhat greater than the combined weight of the. saw sash and several saw blades 11. For example, a typical sawmill of the invention is equipped with a saw sash and saw blades Weighing 60() pounds. Each of the counterweightsv 25 should weigh approximately 650 pounds. The exact weight of the counterweights is not critical, and is determined for each different size of sawmill by actually testing for best results in the elimination of vibration. Inasmuch as individual saw blades are often added or taken away for particular instances ofV use of any given sawmill, it is preferred that the counterweights have provision, for example, as indicated at 25a, Figs. 2 and 3, for the addition or subtraction of weight in relatively small increments. As illustrated,- the additional weight 25a may be in the form ofproperly sized plates bolted to the counterweights.

Fromthe above,v it can be seen that the saw sash and contained` saw blades are almost perfectly counterbalanced in their reciprocative strokes during operation of the sawmill. The relative positions ofthe counterweights and of. the sawv sash during a complete 360 rotation of the crankshaftsare indicated in Figs. l, 6, 7, and 8. Fig. 1 shows these relative positions at the upper termination of areciprocative stroke; Fig. 6, at a point approximatelyy midway between the upper and lower terminations of a reciprocative stroke. during the downstroke in the particular sawmill concerned; Fig. 7, at the lower termination; of a reciprocative stroke; and Fig. 8, approximately midway of a reciprocative stroke during the upstroke of the particular sawmill concerned.

It has lbeen found in actual practice,L that this counterbalancing system enables a sawmill to be operated substantially without vibration, and enables. the base of the structural supporting frame, here the slab base 15, to serve in many instances as a foundation, in place of the massive and costly reinforced. concrete foundations customarily used for the anchoring of conventional sawmills.`

While it is possible to utilize the present counterbalancing system in sawmills employing conventional slideway 4 guides for the saw sash, I have provided a unique pivotal mounting for the saw sash. Such mounting enhancesV the operative effectiveness of the counterbalancing system, and, in turn, is rendered simpler and less costly in construction by reason of such counterbalancing system.

The pivotal mounting system induces the reciprocated sash to travel in true rectilinear fashion throughout both upward and downward strokes, without slideway guides of any kind. Thus, the usual rubbing friction accompanying reciprocation within a conventional slideway guide arrangement is completely eliminated. Reciprocation of the saw sash is easier and smoother, enabling my counterbalancing system to perform with highest efficiency.

From a generalized standpoint, the pivotal mounting which induces the saw sash to execute strictly straightline reciprocation comprises a linkage system having a pair of upper suspension arms and a pair of lower suspension arms, the respective suspension arms of each pair being spaced apart laterally of the saw sash and pivotally connected thereto. Opposite ends of such suspension arms have individual, floating, pivotal connecttions with respective pivotal points of suspension which are fixed relative to the structural framework of the.

machine.

The sets of upper and lower fixed points of suspension are spaced' apart by a distance equal to that by which the sets of upper and lower pivotal connections of suspension arms to saw sash are spaced apart. The sets ofupper and lower floating pivotal connections are similarly spaced apart.

Corresponding, floating, pivotal connections of the upperv and lower sets are interconnected by alinkage system having a lever arm connection with one of the suspension arms of the mounting.

As illustrated, a pair of upper suspension arms 26 and 27, Fig. 4, are rigidly affixed to opposite ends of a shaft 28 having stub ends journaled in respective journal boxes 29 and 30. The latter are rigid on respective brackets 31 and 32, which, in turn, are rigidly attached to respectively opposite ends of a shaft 33 having stub ends journaled in respective journal boxes 34 and 35, the latter being rigidly attached to the respective end frames 16 of the structural framework of the machine, as by means of brackets 36 and 37. Such suspension arms 26 and 27 are pivotally attached tothe upper end of the saw sash 10,y at opposite lateral sides thereof, as indicated at 38 and 39, respectively.

A pair of lower suspension arms 40 and 41, Figs. 2 and 5, are rigidly afxed to opposite ends of a shaft 42 having lower suspension arms 40 and 41 are pivotally attachedto the lower end of the saw sash 10, at opposite lateralv sides thereof, as indicated at 52 and 53, respectively.

The floating upper journals 29, 3l) and the floating lower journals 43, 44 constitute the sets of upper and lower floating pivotal connections, respectively, for the respective pairs of upper and lower suspension arms 26, 27 and 40, 41; while the fixed upper journals 34, 35 and the fixed lower journals 48, 49 constitute the sets of upper and lower fixed points of suspension for such sets of upper and lower floating pivotal connections.

The lateral spacing of the paired pivotal connections is equivalent in the several upper and lower sets, and the spacing between corresponding sets considered4 longitudinally of the saw sash is likewise equivalent, thereby producing a symmetrical, four-point, suspension system. While' it is preferred that the said lateral spacing of upper given instance by physically constraining the` saw sash to reciprocate rectilinearly, and by testing,during reciprocation thereof, for the position for pivot axis 55 which gives substantially a minimum longitudinal component the irmest possible mounting from a practical standpoint,

it should -be realized that these spacings are not critical, and may be varied without disturbing the operation of the suspension system as such.

As mentioned hereinbefore, the upper and lowersets of floating pivots are interconnected for synchronous movement by linkage, which has a rigid lever arm connection with one of the suspension arms and a corresponding provision `for idling oscillation to accommodate arcuate travel of the suspension arms as the saw sash reciprocates.

In the form illustrated, an articulative link is provided at one side of they saw sash by a rod 54 pivotally connected at 55 to an arm 56, the pivot axis extending parallel with the plane of the saw sash so that articulation of the link is perpendicular to such saw sash. The opposite end of rod 54 is pivotally connected to a relatively short lever arm 57, which extends rigidly from shaft 33 so as to be, in effect, rigid with the upper set of floating pivots. The opposite end of arm 56 is rigidly connected to shaft 42, so as to be, in effect, rigidly connected to lower suspension arms 40 and 41 and to provide therewith one of the lever arms of a bell crank.

A non-articulative, synchronizing link is provided at the opposite side of the saw sash by a rod S8, pivotally connected at its upper end to a relatively short lever arm 59, and at its lower end to a similar lever arm 60. The lever arm 59 extends from rigid connection with shaft 33, and, thus, in effect, with floating journal box bracket 32 and the pivotal mounting for oating shaft 28, while the lever arm 60 extends from rigid connection with shaft 47, and, thus, in effect, with floating journal box bracket 46 and the pivotal mounting for oating shaft 42.

It is desirable that a brace 61, Fig. 9, rigidly connect the outer ends of the arms 40 and 56, which are component to the bell crank formation referred to above.

In operation, my counterbalancing system for the reciprocating saw sash largely eliminates the side thrust ordinarily accompanying saw sash reciprocation of conventional sawmills, thereby making it possible for my pivotal mounting system to be of considerably lighter construction than would otherwise be the case. Furthermore, with my pivotal mounting saw sash reciprocation is as truly rectilinear as could be desired for practical purposes.

It can be seen from Figs. 9 and l0, where the motion is graphically depicted, that in this instance the articulative link, as made up of rod 54 and lever arm 56, articulates in a plane which is perpendicular to the plane of the saw sash 10, the articulative pivot 55 thereof oscillating along a path of variable radius due to the floating nature of the end pivots. Meanwhile, the floating pivots provided by journal boxes 29, 30, 43, and 44 oscillate in respective arcs about the pivot axes of their respective xed points of suspension. The full lines represent the relative positions of the several parts at the upper termination of a reciprocative stroke of the saw sash 10, the dotted lines represent the relative positions approximately midway between the upper and lower terminations of a reciprocative stroke, and the broken lines represent the relative positions at the lower termination of a reciprocative stroke.

It should be noted that, for any given variation in length of the suspension arms, where no equivalent variation is made in the pivotal mounting system as a whole, the length of the lever arm 56 will vary to an extent necessary to maintain oscillatory travel of the pivot axis 55 along a substantially similar path of variable radius. The proper length of arm 56 may be determined in any t for the oscillatory travel of pivot axis 55.

As a guide to the particular path of Variable radius found by applicant to give very satisfactory results in practice, a typical sawmill of the invention embodies a saw sash wherein the distance between the attachment pivots 38 and 52 or the attachment pivots 39 and 53 of the respective paired sets thereof is fifty-eight inches, the

respective suspension arms are twenty-eight inches long between pivot centers, the arm 56 is twenty-two inches long between pivot centers, therod 54 is thirty-six and three-fourths inches long between pivot centers, the effective` length of arm 57 as measured directly between pivot centers is eight and nine-sixteenths inches, the link 58 is fifty-eight inches long between pivot centers, arms 59 and 60 are each seven inches long, and thel distances between the axes of journal boxes 44 and 47, on the one hand, and journal boxes 30 and 35, on the other hand, are each live and one-half inches.

The pivotal mounting system for the saw sash is diagrammatically illustrated in Fig. 1l from the standpoint of its status herein as a subcombination representing a mechanical movement, as such. There, single pivots 35 and 49 represent the paired sets of lixed journal boxes 34, 48 and 35, 49, respectively, and constitute the xed pivot axes of a paired set of bell cranks. The pivots designated 30 and 44 represent the pivotal attachment of the suspension arms to the respective paired sets of oating journal boxes 29, 43 and 30, 44. The pair of upper suspension arms 26 and 27 are represented by the single line designated 27, and the pair of lower suspension arms 40 and 41 are represented by the single line 41. The saw sash or any other body to be reciprocated is designated 10, and the pair of upper pivots 38, 39 is represented by the single pivot 39, while the pair of lower pivots 52, 53 is represented by the single pivot 53. The rigid link 58 is designated such, as are the component elements 54 and 56 and the pivot 55 of the articulative link. Also, the arms 57, S9, and 60 and the brace 61 are designated as such. The distances between journal centers are represented by the single lines 62 and 63.

Thus, in effect, the system embodies a paired set of bell cranks having the arms 59, 62 and 60, 63, respectively, and the fixed pivot axes 35 and 49, respectively. The arm 57 extends rigidly from the bell crank arm 62.

Whereas this invention is here illustrated and described with respect to a particular preferred construction, it should be realized that various changes therein and that various dilferent constructions may be made on the basis of the teachings hereof, by those skilled in the art, without departing from the scope of the claims which here follow.

` I claim:

l. In a single sash, gang sawmill, comprising an upright frame having a transverse top frame member; a saw sash equipped with a plurality of saw blades disposed in side by side gang formation within said frame; means mounting said saw sash for rectilinear reciprocation; and means for feeding work into and through the reciprocating saw sash, the combination of a pair of crankshafts spaced apart laterally of the saw sash above said top frame member and extending transversely of the plane of said saw sash, each crankshaft having a single crank at one end thereof projecting beyond said top frame member; bearing means superimposed upon and supported by said top frame member, said crankshafts being journaled by said bearing means intermediate their ends, respectively; a pair of connecting rods pivotally connecting the cranks of said crankshafts to one face of the saw sash at opposite lateral sides and at the upper end thereof; a pair of counter-weights secured to the respective crankshafts in opposition to the cranks thereof for mutually opposed rotation with said crankshafts, said counterweights each having a weight in excess of the weight of the saw sash; a pair of inter-meshed and similar spur gears rigidly axed to the respective crankshafts at the ends thereof opposite the said cranks and beyond the said top frame member; and means connected to one of said crankshafts for rotating the same.

2. The combination recited in claim 1, wherein the counterweights are formed integrally with the cranks of the respective crankshafts.

3. The combinationl recited n claim 1, wherein a lubricant-tight housing encompasses thev spur gears.

References Cited in the leof this patent UNITED STATESv PATENTS 491,295 Robinson Feb. 7, 1893 8 Wilkin May 31, Connell Feb. 18, Moses Dec. 29, Kaufmann May 6, Bruck Mar. 13,

FOREIGN PATENTS Great Britain Feb. 28,

Sweden Jan. 27, Switzerland Aug. 16, Switzerland Feb. 1, Germany Sept. 26, Germany Jan. 12, 

